Biochemical and structural aspects of transiently and stably expressed mutant desmin in vimentin-free and vimentin-containing cells.
Eur J Cell Biol
; 58(1): 108-27, 1992 Jun.
Article
en En
| MEDLINE
| ID: mdl-1644057
ABSTRACT
Using immunoelectron microscopy it is demonstrated that desmin subunits missing their complete carboxy-terminal domain are incapable of homopolymeric filament formation in vivo. Furthermore it is shown that, in vimentin-containing cells, desmin integrates into preexisting vimentin filaments resulting in desmin/vimentin heteropolymers. Removal of the amino-terminal or both nonhelical end domains of desmin increases Triton X-100 solubility of the mutant desmin subunits. Expression of desmin mutants containing deletions in the C-terminal part of the rod in vimentin-free cells results in an increase of the Triton X-100 solubility too. In contrast, if expressed in vimentin-containing cells, these mutant subunits remain in the Triton X-100 insoluble fraction. Deletion of the nonhelical carboxy-terminal domain only has no effect on solubility. In vimentin-free cells, stably expressed desmin subunits missing their amino-terminal domains display a slightly higher turnover rate compared to wild-type desmin. Transiently expressed desmin subunits missing 18 or more carboxy-terminal residues of the rod domain are rapidly degraded in vimentin-free cells. In vimentin-containing cells, turnover rates were much less pronounced. Finally, by using site-directed mutagenesis, we were able to map specific residues important for de novo filament assembly within the amino-terminal domain and in the conserved part at the C-terminus of the alpha-helical domain.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Vimentina
/
Filamentos Intermedios
/
Desmina
Límite:
Humans
Idioma:
En
Revista:
Eur J Cell Biol
Año:
1992
Tipo del documento:
Article
País de afiliación:
Países Bajos